1. Field of the Invention
The present invention generally relates to a non-volatile memory, in particular, to a data preserving method and a data accessing method for a non-volatile memory.
2. Description of Related Art
Generally speaking, non-volatile memories (for example, a flash memory) are always faced with the problem of data instability caused by, for example, bad blocks, write disturb, and read disturb. The problem of read disturb will be explained in detail below.
FIG. 1 is a diagram of memory units in a non-volatile memory. Referring to FIG. 1, read disturb is produced because of the physical characteristic of the non-volatile memory. The address lines 101a, 102a, 101b, 102b, 103b . . . are used for transmitting data voltages or for addressing a data. In other words, if a data in memory unit 101 is to be read, the data in the memory unit 101 is addressed and read through the address lines 101a and 101b, and accordingly a residual voltage is left on the address lines 101a and 101b. Since the address line 101a is shared by the memory units 101, 102, and 103, the residual voltage on the address line 101a may affect the data in the memory units 102 and 103 and may even cause errors to the data in the memory units 102 and 103. Similarly, since the address line 101b is shared by the memory units 101 and 104, the residual voltage on the address line 101b may also affect the data in the memory unit 104 and may even cause error to the data in the memory unit 104.